1. Field of Invention
The present invention relates to a structure for controlling an active mount of a vehicle, and more particularly, to a structure for controlling an integrated active mount of a vehicle which improves traveling performance of a vehicle, not for reducing noise vibration, by providing a control signal with an inverse phase to the phase of the main excitation force of an engine in accordance with traveling conditions through an active mount disposed between the engine and a vehicle body in order to reduce noise vibration of the vehicle.
2. Description of Related Art
In general, the engine of vehicles generates an excitation force due to vibration simultaneously with starting. The excitation force generated by the engine is transmitted to the vehicle body, and generated noise vibration, thereby reducing comfort of the driver. Accordingly, it has been required to develop a technology that minimizes excitation signals transmitted to a vehicle body.
As a technology for minimizing excitation signals transmitted to a vehicle body, an active mount designed to reduce excitation signals generated by an engine and transmitted to a vehicle body, using a mount connecting the engine and the vehicle body of a vehicle, has been known in the art.
FIG. 1 shows an MR FLUID HYDRAULIC MOUNT, that is, a semi-active mount that control the behavior of a power train, using magneto-rheological fluid disclosed in U.S. Pat. No. 7,510,061 B2.
The magneto-rheological fluid is a suspension with soft magnetic particles mixed in liquid synthetic hydrocarbon, in which the magnetized particles shows fluid behavior like common fluid (fluid in a common hydro-mount) by non-uniformly dispersing in the OFF-state, but the particles are arranged in the structure of a fiber and the properties are changed in the ON-state, that is, a magnetic field is applied (shear stress=viscosity×shear rate+yield shear stress). The yield shear stress is proportioned to the applied magnetic field and the intensity of the magnetic field is proportioned to the intensity of the current flowing in a coil.
Accordingly, the semi-active mount using magneto-rheological fluid has a structure that improves noise vibration performance or traveling performance of a vehicle in accordance with the driving conditions by injecting magneto-rheological fluid with the properties into a mount and applying a magnetic field to the magneto-rheological fluid so that the shear stress of the fluid changes and the dynamic stiffness and damping characteristic change in real time.
Accordingly, according to the configuration, vibration noise and traveling performance are effectively improved by controlling the dynamic stiffness and damping characteristic of a mount by changing the current applied to the coil in accordance with the driving conditions, in order to reduce vibration by blocking a current input signal so that the stiffness of the mount decreases in normal traveling, and to improve the traveling performance by inputting a current so that the stiffness of the mount in sporty traveling.
However, the semi-active mount using magneto-rheological fluid has a defect that although it is possible to increase the characteristics more than the characteristics, which are set in designing, it is impossible to reduce the characteristics and to select vibration components (frequency) to reduce, when operating the actuator.
On the other hand, as another active mount, an active mount using an electric actuator has been used in the art.
FIG. 2 shows one of active mounts using an electric actuator in the art.
The active mount using an electric actuator has a bidirectional control structure that operates the actuator, using Lorenz force between a permanent magnet and a coil to which a current is applied, and moves a decoupler up/down using the actuator, thereby reducing the dynamic characteristics of the mount in a desired section and reducing vibration transmission rate of a power train.
Accordingly, the active mount having the structure reduces the dynamic characteristics of the mount by vibrating the decoupler with the same phase as that of vibration inputted to the mount, by measuring or estimating vibration inputted to the active mount and changing the control signal applied to the coil. In this configuration, it is possible to set Lorenz force in different directions by applying the current in the forward direction or the backward direction, and thus the direction of the control force can be changed.
However, the active mount using an electric actuator still has a defect that it is possible to decrease the characteristics more than the characteristics, which are set in designing, but it is impossible to increase them, when operating the actuator.
FIG. 3 shows an electromagnetic integrated active mount using an electromagnetic actuator disclosed in U.S. Pat. No. 6,641,120 B2.
The electromagnetic integrated active mount using an electromagnetic actuator has a structure, which includes a rubber actuating plate under an injection chamber and improves an insulation rate against vibration transmitted to a vehicle body through a mount by moving the actuating plate up/down, using the control force (attractive force) of the electromagnetic actuator and the elastic force (restoring force) of the rubber, and changes the volume of the injection chamber and insulates vibration through a reduction in mount characteristic by changing the control signals applied to the electromagnetic actuator in accordance with driving conditions so that the actuating plate moves up/down with the same phase as that of the vibration inputted to the mount.
The dynamic characteristics of the mount is reduced by a controller that estimates vibration inputted to the mount from the vehicle information and vibrates the decoupler by applying a corresponding current with the same phase to the coil.
However, the electromagnetic integrated active mount can attract conductors around, using input signals, but the conductors around are returned by the restoring force of the actuating plate made of rubber. Accordingly, only unidirectional control is possible.
Further, the integrated active mount using an electromagnetic actuator, similar to the active mount using an electric actuator, has a defect that that it is possible to decrease the characteristics more than the characteristics, which are set in designing, but it is impossible to increase them, when operating the actuator.
The information disclosed in this Background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.